Our sources

We only publish numbers we can trace to a primary source: the original study, official statistics, or the organization's own reporting. Secondary retellings, influencer polls, and unattributed "studies show" claims are rejected at the fact-gate.

Primary sources currently cited

• Journal of Social and Personal Relationships (2018)Same two self-report studies as hall-hours-casual.
• Utrecht University (2009)Same panel study as mollenhorst-network-turnover.

What we rejected, and why

This list matters as much as the one above. These are figures that circulate widely in writing about adult friendship and loneliness and that we could not trace to a primary source, so they do not appear anywhere on this site.

• It takes 200 hours to make a best friend / the 200-hour rule / the 50-hour rule — The figures are real (see hall-hours-*) but this phrasing is not what the research supports. Hall reports averages from two specific self-report samples — recent movers and university freshmen — and states that time alone is not sufficient and that time spent working alongside someone counts far less. Calling it a 'rule' converts an average into a law and drops the population entirely. Use the approved entries with their constraints, never this phrasing.
• You lose half your friends every seven years — Traceable to the Utrecht panel study (see mollenhorst-*), but the popular phrasing drops the finding that makes it meaningful: network SIZE stayed stable — people were replaced, not simply lost. The claim as usually written implies steady decline, which the same research contradicts. Use mollenhorst-network-turnover with its constraint.
• The average adult has X close friends / people have fewer friends than they did N years ago (any specific figure) — No primary source opened and verified for this site yet. Widely circulated with numbers attributed variously to Gallup, Pew and the Survey Center on American Life, often without the question wording, which differs between them. Until an entry exists here with the exact question and base, /no-friends/is-it-normal/ and /statistics/ may not publish a figure — per content-spec §2, that page does not ship without verified numbers.
• Loneliness is as bad for you as smoking 15 cigarettes a day — A health claim, and this site does not make health claims (content-spec §0.5 YMYL boundary). The figure derives from a meta-analysis on mortality risk and is routinely stripped of its context. Out of scope regardless of whether it could be sourced.

The rules

1. Named source in the same sentence as the number, with the year.
2. Primary source only — we link the origin, not an article about it.
3. Dated verification: every statistic carries its verification date on the statistics page.
4. Unverifiable → unpublished. No exceptions.